With the progress of the broadband in recent years, the request for high-speed wireless communication of a large capacity is growing. For example, as regards amplifiers for a base station for a portable telephone set, those of the third generation have become widespread and it appears that base station amplifiers further progress to the fourth generation in the future, toward increase of the capacity. Further, it is estimated that also a new communication method (WiMAX) is placed into practical use and increase of the capacity further progresses in the future. Therefore, further increase of the output power and the efficiency, further miniaturization and further reduction of the cost are demanded for transmission/reception modules.
Meanwhile, for example, for a radar module (transmission/reception module including an amplifier), increase of the output power and increase of the bandwidth toward enhancement of a performance such as increase of the detection distance or enhancement of the resolution, and increase of the efficiency toward reduction of the operational cost and miniaturization of a cooler are demanded. Further, for example, in a phased array radar, it is necessary to dispose transmission/reception modules (radar modules) including an amplifier in an array in a small space, and further miniaturization of transmission/reception modules is demanded.